Dynamically adjusting communication channel bandwidth

ABSTRACT

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for adjusting communication channel bandwidth. In some implementations, a method includes determining to change a bandwidth of a wireless communication channel on which a transmitter and receiver communicate. In response, and while the transmitter and the receiver maintain data communication on the wireless communication channel, a target value and rate of change is determined for each of one or more communication parameters of the wireless communication channel. The rate of change is a rate at which the communication parameter can be changed over time while continuing to transfer data on the wireless communication channel. Data is provided to the transmitter. The data can cause, for each communication parameter, the transmitter to gradually adjust the communication parameter using the rate of change until the communication parameter reaches the target value.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/858,858, filed Dec. 29, 2017, now allowed, which is incorporated byreference in its entirety.

BACKGROUND

Communications satellites are commonly used to transmit data betweengateways and terminals. For example, communications satellites are usedto provide Internet access to many users. Communications satellites canalso be used for cellular backhauling. In both examples, the amount ofbandwidth required by a satellite terminal can vary over time.

SUMMARY

In some implementations, a communications system can dynamicallyre-define wireless communication channels while the channels are in use,in a manner that does not disrupt data transfer or require buffering ofdata. For example, the TDM frequency bandwidth of a satellitecommunication channel can be changed while a transmitter and receivermaintain data communication over the course of the change. For example,a transmitter can adjust communication parameters (e.g., centerfrequency or frequency bandwidth) of a wireless communication channelgradually so that a receiver that is receiving data transmissions fromthe transmitter can track the wireless communication channel as it isadjusted. For example, receivers that are configured to receive dataover a particular wireless communication channel can typically adjust tominor changes (e.g., less than a threshold amount) to the wirelesscommunication channel due to normal fluctuations in the actual centerfrequency or frequency bandwidth of the wireless communication channel.By gradually adjusting the communication parameters at (or below) a rateof change to which the receiver can adapt, the transmitter and receivercan maintain an active communication link while the channel parametersare being adjusted.

A computing device can determine to adjust the center frequency orbandwidth of the wireless communication channel. The determination canbe made based on expected bandwidth demand, in response to a request toadjust the bandwidth of the wireless communication channel, or inresponse to adjustments to communication parameters of one or more otherwireless communication channels.

Some prior approaches for changing the frequency bandwidth for a channelhave involved relatively abrupt changes in communication parameters.These abrupt changes typically disrupt data communication over thewireless communication channel, or require buffering of data in advanceto avoid disruption. Further, some changes have incurred significantdelays in data transfer while control messages are exchanged and theadjustments to channel parameters are made. If data buffering is used tominimize disruption, additional planning and data storage resources areneeded to buffer data until data communication is re-established on thewireless communication channel.

By contrast with prior approaches, the technique discussed in thisdocument allows gradual, coordinate adjustment of the communicationparameters so that the data communication is not disrupted, even aschannel parameters such as frequency bandwidth and center frequency arechanged. An active communication link between the transmitter and thereceiver can be maintained before the communication parameters areadjusted, while the communication parameters are being adjusted, andafter the wireless communication parameters are adjusted. This reducesthe latency in transmitting data, reduces the amount of data storageresources needed, allows for the dynamic adjustment of wirelesscommunication channels without disrupting data communication, and allowsfor the dynamic expansion of a wireless communication frequency spectrumwithout data disruption or data loss.

Adjustments to the communication parameters of multiple communicationchannels can be coordinated such that the wireless communicationchannels do not overlap, which could introduce interference onto one ormore of the wireless communication channels. For example, if thefrequency bandwidth of a first wireless communication channel is goingto be expanded, the center frequency or frequency bandwidth of a secondwireless communication channel adjacent to the first wirelesscommunication channel (and potentially other wireless communicationchannels) may be adjusted to prevent overlap in the frequency ranges ofthe two wireless communication channels. As described below, the starttimes of each adjustment can be determined based on the rates of changeof the communication parameters, the current values of the communicationparameters, and the target values of the communication parameters toavoid frequency overlap between the wireless communication channels andto prevent or reduce interference between the wireless communicationchannels.

The techniques for adjusting communication parameters described hereinallow for more efficient use of a satellite frequency spectrum. Forexample, the satellite frequency spectrum can be dynamicallyre-allocated to adjust for varying demand among the satellite wirelesscommunication channels within the spectrum. The frequency ranges of thesatellite communication channels can be adjusted (e.g., increased ordecreased, and/or or shifted) to align spectrum usage to current demandon a per-channel basis and/or to avoid or reduce interference betweenthe channels. For example, if the data demand of a first satellitecommunication channel is increasing, the bandwidth of other satellitechannels that have more than enough bandwidth can be dynamically reducedand the other satellite channels can be dynamically shifted along thefrequency spectrum to allow for an expansion of the bandwidth of thefirst wireless communication channel. The re-allocation can also occurwithout delay in satellite communication and without data loss.

In one general aspect, the techniques disclosed herein describe methodsof adjusting communication parameters of wireless communicationchannels. According to some of the methods, one or more computingdevices determine to change a bandwidth of a wireless communicationchannel on which a transmitter and a receiver communicate. In responseto the determination, and while the transmitter and the receivermaintain data communication on the wireless communication channel: theone or more computing devices determine, for each of one or morecommunication parameters of the wireless communication channel, a targetvalue for the communication parameter; identify a rate of change foreach of the one or more communication parameters; and provide, to thetransmitter and for each of the one or more communication parameters,data that causes the transmitter to gradually adjust the communicationparameter using the rate of change for the communication parameter untilthe communication parameter reaches the target value for thecommunication parameter. The one or more communication parameters caninclude at least one of (i) a center frequency of the wirelesscommunication channel or (ii) a frequency bandwidth of the wirelesscommunication channel. The rate of change for each communicationparameter can be a rate at which the communication parameter can bechanged over time while continuing to transfer data on the wirelesscommunication channel.

In some implementations, the rate of change for each communicationparameter is based on a maximum rate of change for the communicationparameter for which the receiver is capable of tracking changes to thecommunication parameter and maintaining communication with thetransmitter over the wireless communication channel.

In some implementations, the transmitter includes a satellitetransmitter. The receiver can include a satellite receiver. Thesatellite transmitter transmits data to the satellite receiver by way ofa satellite and using a satellite communication link over the wirelesscommunication channel.

In some implementations, the transmitter gradually adjusts each of theone or more communication parameters over a time period. The transmitterand the receiver maintain an active communication link over the wirelesscommunication channel during the time period. The receiver receives,from the transmitter, multiple data transmissions over the wirelesscommunication channel during the time period. A value of each of the oneor more communication parameters can be different for at least two ofthe data transmissions.

In some implementations, the transmitter gradually adjusts each of theone or more communication parameters in multiple increments. A value ofthe one or more communication parameters is different for eachincrement. The receiver receives, from the transmitter and over thewireless communication channel, a data transmission at a multitude ofthe increments.

Some implementations include determining to change one or more secondcommunication parameters of a second wireless communication channelbased on the change in bandwidth of the wireless communication channel.A second transmitter and a second received communicate on the secondwireless communication channel. For each of one or more secondcommunication parameters of the second wireless communication channel,the one or more computing devices can determine a second target valuefor the second communication parameter. The one or more secondcommunication parameters can include at least one of (i) a centerfrequency of the second wireless communication channel or (ii) afrequency bandwidth of the second wireless communication channel. Theone or more computing devices can identify a second rate of change foreach of the one or more second communication parameters. The second rateof change for each second communication parameter can be a rate at whichthe second communication parameter can be changed over time whilecontinuing to transfer data on the second wireless communicationchannel. The one or more computing devices can provide, to the secondtransmitter and for each of the one or more second communicationparameters, data that causes the second transmitter to gradually adjustthe second communication parameter using the second rate of change forthe second communication parameter until the second communicationparameter reaches the second target value for the second communicationparameter.

Some implementations include coordinating the gradual adjustment to theone or more communication parameters by the transmitter and the gradualadjustment to the one or more second communication parameters by thesecond transmitter. The one or more computing devices can determine, forthe transmitter, a first start time for the transmitter to startgradually adjusting each of the one or more communication parameters.The one or more computing devices can determine, for the secondtransmitter, a second start time for the second transmitter to startgradually adjusting each of the one or more second communicationparameters. The one or more computing devices can provide the firststart time to the first transmitter and provide the second start time tothe second transmitter.

In some implementations, the first start time and the second start timeare determined such that the communication channel and the secondcommunication channel do not overlap in transmission frequencies duringthe adjustment to the communication parameters and the adjustment to thesecond communication parameters.

In some implementations, determining to change the bandwidth of thewireless communication channel can include determining to change thebandwidth based on at least one of (i) receiving, from the transmitter,a request to change the bandwidth, (ii) historical bandwidth demand ofthe transmitter, (iii) an adjustment to a center frequency or frequencybandwidth of a second wireless communication channel, (iv) an additionof a third wireless communication channel to a frequency spectrum thatincludes the wireless communication channel, or (v) removal of a fourthwireless communication channel from the frequency spectrum.

Other embodiments include corresponding systems, apparatus, and softwareprograms, configured to perform the actions of the methods, encoded oncomputer storage devices. For example, some embodiments include asatellite terminal and/or a satellite gateway configured to perform theactions of the methods. A device or system of devices can be soconfigured by virtue of software, firmware, hardware, or a combinationof them installed so that in operation cause the system to perform theactions. One or more software programs can be so configured by virtue ofhaving instructions that, when executed by data processing apparatus,cause the apparatus to perform the actions.

The details of one or more embodiments of the subject matter describedin this specification are set forth in the accompanying drawings and thedescription below. Other features, aspects, and advantages of thesubject matter will become apparent from the description, the drawings,and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram that illustrates an example of a system foradjusting communication channel bandwidth.

FIG. 2 is a diagram that illustrates an adjustment to the communicationchannel bandwidth of a wireless communication channel.

FIG. 3 is a diagram that illustrates an adjustment to the communicationchannel bandwidth of a wireless communication channel.

FIG. 4 is a diagram that illustrates adjustments to the communicationchannel bandwidth of multiple wireless communication channels.

FIG. 5 is a diagram that illustrates adjustments to the communicationchannel bandwidth of multiple wireless communication channels.

FIG. 6 is a diagram that illustrates adjustments to multiple wirelesscommunication channels.

FIG. 7 is a flow diagram that illustrates an example process foradjusting communication channel bandwidth.

Like reference numbers and designations in the various drawings indicatelike elements.

DETAILED DESCRIPTION

FIG. 1 is a diagram that illustrates an example of a system 100 foradjusting communication channel bandwidth. The system includes asatellite gateway 150 that communicates with a satellite terminal 120 byway of a satellite 140. The satellite gateway 150, the satelliteterminal 120, and the satellite 140 can be part of a satellitecommunication network that includes one or more satellites, one or moresatellite gateways, and one or more satellite terminals.

In the illustrated example, the satellite terminal 120 is being used forcellular backhauling. In a cellular backhauling operation, the satelliteterminal 120 provides satellite data communication between mobile phones115 and the gateway 150. The mobile phones 115 can send data to, andreceive data from, a cell tower 110. The satellite terminal 120 canreceive data from the mobile phones 115 by way of the cell tower 110 andprovide the data to the gateway 150 by way of the satellite 140.Similarly, the satellite terminal 120 can receive data intended for amobile phone 115 from the gateway 150 by way of the satellite 140 andprovide the data to the mobile phone 115 by way of the cell tower 110.The techniques described herein can also be applied to other uses ofsatellite terminals and other types of satellite terminals, such asmobile satellite terminals.

The satellite terminal 120 includes a transceiver 122 with a transmitter124, a receiver 126, and a channel adjuster 128. The transmitter 124transmits data over a wireless communication channel between thesatellite terminal 120 and the satellite 140. Similarly, the receiver126 receives data over a wireless communication channel between thesatellite terminal 120 and the satellite 140. As described below, thechannel adjuster 128 can adjust channel parameters of the satellitetransmitter 124.

The satellite gateway 150 also includes a transceiver 151 with atransmitter 152 and a receiver 153. The transmitter 151 transmits dataover a wireless communication channel between the satellite gateway 150and the satellite 140. Similarly, the receiver 153 receives data over awireless communication channel between the satellite terminal 150 andthe satellite 140.

Each wireless communication channel used by the satellite terminal 120,the satellite gateway 150, and the satellite 140 can be defined by arange of frequencies between a lower frequency and an upper frequency.The range of frequencies for a wireless communication channel includes acenter frequency that is measure of a central frequency between theupper and lower frequencies of the wireless communication channel.Wireless communication channels for satellite communication aretypically within the Ka-band, which includes frequencies in the range of26.5-40 gigahertz (GHz), or the Ku-band, which includes frequencies inthe range of 12-18 GHz.

An example wireless communication channel for satellite communicationmay have a center frequency of 30 GHz, an upper frequency of 30.1 GHz,and a lower frequency of 29.9 GHz. The frequency bandwidth of a wirelesscommunication channel is equal to the difference between the upperfrequency and the lower frequency of the wireless communication channel.For this example, the frequency bandwidth would be 0.2 GHz (30.1GHz-29.9 GHz).

In some implementations, the satellite terminal 120, the satellite 140,and the satellite gateway 150 use time-division multiplexing (TDM)techniques for transmitting and receiving data. In this example, thewireless communication channels used to exchange data between thesatellite terminal 120 and the satellite gateway 150 can be persistentcommunication links that are maintained for an indefinite period oftime. This allows the satellite terminal 120 and the satellite gateway150 to perform cellular backhauling operations.

The symbol rate of a wireless communication channel is based on thefrequency bandwidth and the coding of the wireless communicationchannel. In general, the symbol rate increases with an increase infrequency bandwidth. For purposes of brevity, the bandwidth adjustmentsof the system 100 of FIG. 1 are described in terms of adjustments infrequency bandwidth of wireless communication channels. However, thesame (or similar) techniques can be used to adjust the symbol rates ofthe wireless communication channels. For example, the target values andrates of change described below can be in terms of symbol rates ratherthan frequency bandwidth.

The transceiver 151 of the satellite gateway 150 is in datacommunication with a computing device 160, e.g., over a wired, wireless,or network connection. The computing device 160 includes a bandwidthcontroller 161. The bandwidth controller 161 can manage the wirelesscommunication channels for a set of one or more satellite terminals, oneor more satellite gateways, and one or more satellites that communicatewithin a particular frequency spectrum. The set of one or more satelliteterminals, one or more satellite gateways, and one or more satellitesinclude the satellite terminal 120, the satellite gateway 150, and thesatellite 140.

The bandwidth controller 161 can determine when to add a wirelesscommunication channel within the frequency spectrum and when to remove awireless communication channel from the frequency spectrum. Thebandwidth controller 161 can also determine and adjust communicationparameters of the wireless communication channels within the frequencyspectrum. The communication parameters for a wireless communicationchannel adjusted by the bandwidth controller 161 can include the centerfrequency of the wireless communication channel and/or the frequencybandwidth of the wireless communication channel.

For example, the bandwidth controller 161 can expand the frequencybandwidth of a wireless communication channel in response to a requestto expand the frequency bandwidth (e.g., received from a transmittertransmitting data over the wireless communication channel) or inresponse to historical bandwidth demand of the transmitter transmittingdata over the wireless communication channel. The bandwidth controller161 can also adjust the frequency bandwidth and/or center frequency of awireless communication channel in response to an adjustment to a centerfrequency or frequency bandwidth of a different wireless communicationchannel, in response to an addition of a new communication channel to afrequency spectrum that includes the wireless communication channel, inresponse to removal of a wireless communication channel from thefrequency spectrum, and/or to make room in the frequency spectrum incase another wireless communication channel is added later.

In the example of FIG. 1, during stage (A), the satellite transmitter124 transmits a request 130 for a bandwidth adjustment for the wirelesscommunication channel (“Channel 1”) on which the transmitter 124 istransmitting data. For example, if there is an increase in the number ofmobile phones 115 requesting to exchange data by way of the cell tower120 or an increase in the amount of data that the mobile phones 115 arerequesting to exchange by way of the cell tower 120, the transmitter 124can transmit a request 130 for additional bandwidth to the satellite140. Similarly, if there is a decrease in the number of mobile phones115 requesting to exchange data by way of the cell tower 120 or adecrease in the amount of data that the mobile phones 115 are requestingto exchange by way of the cell tower 120, the transmitter 124 cantransmit a request 130 for a reduction in bandwidth to the satellite140. The request 130 can specify an amount of additional or lessbandwidth requested or simply request more or less bandwidth.

During stage (B), the satellite 140 transmits forwards the request 130to the satellite gateway 150.

During stage (C), a bandwidth manager 162 of the bandwidth controller161 receives the request 130 (or the data of the request 130) anddetermines whether to adjust one or more communication parameters (e.g.,the center frequency or the frequency bandwidth) of Channel 1. In someimplementations, the bandwidth manager 162 determines whether to adjustthe frequency bandwidth of Channel 1 based on communication parametersof other wireless communication channels (e.g., Channel 2 or anotherchannel). For example, if the other wireless communication channels inthe frequency spectrum (e.g., the frequency spectrum managed by thebandwidth controller 161) are at or near capacity and there is noadditional available bandwidth in the frequency spectrum, the bandwidthmanager 162 can determine to not increase the bandwidth of Channel 1. Ifthe bandwidth of another wireless communication channel in the frequencyspectrum can be reduced or if there is available bandwidth in thefrequency spectrum, the bandwidth manager 162 can determine to increasethe bandwidth of Channel 1.

To determine whether to adjust the frequency bandwidth of Channel 1based on the communication parameters of other wireless communicationchannels, the bandwidth manager 162 can determine an amount of frequencybandwidth being used (e.g., by determining a sum of the frequencybandwidths of the wireless communication channels that are active in thefrequency spectrum). The bandwidth manager 162 can then subtract theamount of frequency bandwidth being used from the total frequencybandwidth of the frequency spectrum to determine the amount of frequencybandwidth available in the frequency spectrum. If there are buffers offrequencies between adjacent carriers (e.g., to prevent or reduceinterference between channels), the amount of bandwidth consumed by thebuffers can be subtracted from the amount of frequency bandwidthavailable. If there is frequency bandwidth available, the bandwidthcontroller 162 can increase the frequency bandwidth of Channel 1.

In this example, the bandwidth manager 162 has determined to increasethe bandwidth of Channel 1 by 60 megahertz (MHz). The original frequencybandwidth of Channel 1 is 100 MHz. Thus, target frequency bandwidthafter the adjustment is 160 MHz.

In another example, the bandwidth manager 162 can determine to adjustthe frequency bandwidth of the Channel 1 based on historical dataregarding the bandwidth demand of Channel 1 and/or historical dataregarding the bandwidth demand of the transmitter 124 and the receiver153. For example, the bandwidth controller 161 can monitor the bandwidthdemands of Channel 1 and other channels (or pairs of transmitters andreceivers) and store the monitored data in a historical data store 169,which can be implemented in one or more data storage devices (e.g., oneor more hard drives, flash memory, etc.). If the historical dataindicates that more data is transmitted over Channel 1 (and/or betweenthe transmitter 124 and the receiver 153) during particular time periods(e.g., during daylight hours), the bandwidth manager 162 can determineto increase the bandwidth of Channel 1 at or before the particular timeperiods. In this example, the bandwidth manager 162 can also determineto reduce the frequency bandwidth of Channel 1 after the particular timeperiods (e.g., during nighttime hours). The bandwidth manager 162 canuse one or more machine learning models trained using the historicaldata to determine when to adjust the frequency bandwidth of Channel 1and the other channels.

In another example, the bandwidth manager 162 can determine to adjustthe frequency bandwidth of Channel 1 based on an adjustment to thefrequency bandwidth of another wireless communication channel in thefrequency spectrum, based on an addition of a new wireless communicationchannel to the frequency spectrum, or based on the removal of a wirelesscommunication channel from the frequency spectrum. For example, thebandwidth manager 162 can receive a request to increase the frequencybandwidth of another wireless communication channel. The bandwidthmanager 161 can also determine, based on the historical data, that thefrequency bandwidth of Channel 1 can be reduced. In response, thebandwidth manager 162 can reduce the frequency bandwidth of Channel 1based on the amount of bandwidth needed by Channel 1 and the amount ofadditional frequency bandwidth requested by the other wirelesscommunication channel.

Similarly, if another wireless communication channel is being added tothe frequency spectrum and the frequency spectrum does not have enoughavailable frequency bandwidth for the other wireless communicationchannel, the bandwidth manager 162 can reduce the frequency bandwidth ofChannel 1 based on the amount of frequency bandwidth need by Channel 1and the amount of frequency bandwidth needed for the other wirelesscommunication channel. If a wireless communication channel is removedfrom the frequency spectrum, the bandwidth manager 162 can increase thefrequency bandwidth of Channel 1 to allow for faster communication overChannel 1.

During stage (D), a parameter adjuster 164 of the bandwidth controller164 adjusts the communication parameters of Channel 1 (and optionallyother wireless communication channels) based on the determination toincrease the bandwidth of Channel 1 by 60 MHz. The parameter adjuster164 can adjust the frequency bandwidth of Channel 1 from 100 MHZ to atarget frequency bandwidth of 160 MHz based on the bandwidth manager'sdetermination to increase the bandwidth of Channel 1 by 60 MHz.

The parameter adjuster 162 can maintain the communication channelparameters for each wireless communication channel in a channelparameters data store 167, which can be implemented in one or more datastorage devices. In this way, the parameter adjuster 162 can access thecommunication parameters of the wireless communication channels todetermine how to adjust the communication channel parameters toaccommodate changes in frequency bandwidth for the wirelesscommunication channels and/or additions or deletions of wirelesscommunication channels from the frequency spectrum.

In addition to adjusting the frequency bandwidth of Channel 1, theparameter adjuster 164 can determine to adjust the center frequency ofChannel 1, e.g., based on an adjustment to the frequency bandwidth ofChannel 1. For example, there may be more available frequencies to oneside of the range of frequencies of the Channel 1 (e.g., the upperfrequency side) than the other side (e.g., the lower frequency side). Inthis example, the bandwidth manager 162 can expand Channel 1 to the oneside (or more to the one side than to the other side), by adjusting thecenter frequency of Channel 1 towards to one side and increasing thefrequency bandwidth of Channel 1.

In the example of FIG. 1, the parameter adjuster 164 determined toadjust the center frequency of Channel 1 (f_(c1)) by 20 MHz from acenter frequency of 30 GHz to a target center frequency of 30.02 GHz.For example, there may be more available frequencies above the upperfrequency of Channel 1 than there are below the lower frequency ofChannel 1. The parameter adjuster 164 can shift the frequency band ofChannel 1 by 20 MHz to prevent interference with the wirelesscommunication channel adjacent to Channel 1 on the lower frequency sideof channel 1 below the lower frequency of Channel 1.

The parameter adjuster 164 can also determine to adjust one or morecommunication parameters of one or more other wireless communicationchannels based on the adjustment to the frequency bandwidth ofChannel 1. For example, to accommodate the additional frequencies of thetarget frequency bandwidth of Channel 1, the parameter adjuster 164 candetermine to shift the center frequency of an adjacent wireless channelaway from Channel 1 to prevent interference between the adjacentwireless communication channel and adjusted Channel 1. In anotherexample, the parameter adjuster 164 can determine to shift adjacentwireless communication channels on either side of Channel 1 away fromChannel 1 to prevent interference between the adjacent wirelesscommunication channels and adjusted Channel 1.

In another example, the parameter adjuster 164 can shift multiplewireless communication channels on one or both sides of Channel 1. Forexample, to shift an adjacent wireless communication channel away fromChannel 1, the parameter adjuster 164 can determine that anotherwireless communication channel should be shifted to accommodate theshift to the adjacent wireless communication channel.

The parameter adjuster 164 can determine which wireless communicationchannels for which to adjust communication parameters based on thecurrent communication parameters of the wireless communication channelsin the frequency spectrum, the adjustments to the communicationparameter(s) of Channel 1, and any frequency buffer to maintain betweenpairs of wireless communication channels. For example, the parameteradjuster 164 can determine, based on the center frequency of an adjacentwireless communication channel, the frequency bandwidth of the adjacentwireless communication channel, the target frequency bandwidth ofChannel 1 and the target center frequency of Channel 1, that theadjusted frequency band of Channel 1 will overlap with the frequencybandwidth of the adjacent wireless communication channel. In response,the parameter adjuster 164 can determine that the adjacent wirelesscommunication channel should be shifted.

If the parameter adjuster 164 determines to adjust the communicationparameters of another wireless communication channel, the parameteradjuster 164 can determine target values for the communicationparameters of the other wireless communication channel. For example, ifthe parameter adjuster 164 determines to shift an adjacent wirelesscommunication channel away from Channel 1, the parameter adjuster candetermine a target center frequency for the adjacent wirelesscommunication channel that accomplishes the desired shift.

The parameter adjuster 164 can also coordinate the adjustments ofChannel 1 and other wireless communication channels using start timesfor the adjustments. For example, the parameter adjuster can determine astart time for each communication parameter that is going to beadjusted. The start time for a communication parameter can indicate atime at which a transmitter is to begin adjusting the communicationparameter. If the communication parameter(s) for multiple wirelesscommunication channels are going to be adjusted, the parameter adjuster164 can determine the start time for each communication parameter tocoordinate the adjustments in way that prevents or reduces interferencebetween the wireless communication channels.

The parameter adjuster 164 can determine the start times based on therates of change of the communication parameters, the current values ofthe communication parameters, and the target values of the communicationparameters to avoid frequency overlap between the wireless communicationchannels and to prevent or reduce interference between the wirelesscommunication channels. For example, if the adjustment to Channel 1would cause Channel 1 to overlap in frequencies with another channel(e.g., Channel 2), the parameter adjuster 164 can determine start timesfor changes to Channels 1 and 2 such that Channel 2 is shifted beforeChannel 1 overlaps with Channel 2. If the rate of change for thecommunication parameter(s) of Channel 2 are equal to, or faster than,the rate of change for the same communication parameter(s) for Channel1, the start times for Channels 1 and 2 can be the same. If the rate ofchange for the communication parameter(s) of Channel 2 are equal to, orfaster than, the rate of change for the same communication parameter(s)for Channel 1, the start time for Channel 2 can be earlier than thestart time for Channel 1. Examples of adjustments to wirelesscommunication channels are illustrated in FIGS. 2-5 and described below.

During stage (E), a rate of change identifier 166 identifies a rate ofchange for each wireless communication parameter that is going to beadjusted. The rate of change for a communication parameter is a rate atwhich the communication parameter is to be gradually (e.g.,incrementally or continuously) changed over time. For example, the rateof change for a center frequency can be a frequency value over unit time(e.g., 50 KHz per second). Similarly, the rate of change for frequencybandwidth can be a frequency value over time (e.g., 100 KHz per second).

The rate of change of a communication parameter for a wirelesscommunication channel can be based on the capabilities of the receiverthat is receiving data over the wireless communication channel. Forexample, a receiver may have a maximum rate of change for eachcommunication parameter for which the receiver is capable of trackingthe adjustments to the communication parameter and maintaining an activewireless communication link with the transmitter.

If the transmitter changes the communication parameter at a rate that ishigher than the maximum rate of change, the receiver may not be able totrack the transmitter and the wireless communication link may be lost.If the transmitter changes the communication parameter at a rate that isequal to or less than the maximum rate of change, the receive can trackthe transmitter and maintain the active wireless communication linkwhile the communication parameter is being adjusted at the transmitter.With the active wireless communication link, the receiver can continueto receive data from the transmitter during the adjustment and withoutdisruption. Thus, the rate of change for a communication parameter for areceiver can be equal to or less than the maximum rate of change for thecommunication parameter for the receiver.

The rates of change for each receiver (or wireless communication channelcan be stored in a rate of change data store 168, which can beimplemented in one or more data storage devices. Each rate of change canbe stored with reference to the receiver and/or wireless communicationchannel to which the rate of change applies. For example, the rate ofchange data store 168 can include a table that includes, for eachreceiver, a row that includes the receiver's center frequency rate ofchange and the receiver's bandwidth frequency rate of change.

The rate of change identifier 166 can access the rate of change datastore 168 and retrieve the rate of change for each communicationparameter that is to be adjusted. For example, the rate of changeidentifier 166 can receive, from the parameter adjuster 164, dataspecifying the communication parameters that are being adjusted andretrieve the appropriate rate of change for each communicationparameter. The rate of change identifier 166 can retrieve the rate ofchange for a communication parameter based on the receiver of thewireless communication for which the communication parameter is beingadjusted.

In the example of FIG. 1, the rate of change identifier 166 hasidentified a rate of change of 50 KHz per second for the centerfrequency of Channel 1 and a rate of change of 100 KHz per second forthe frequency bandwidth of Channel 1. These rates of change can be basedon the maximum rates of change of the receiver 153.

The bandwidth controller 161 can provide data that specifies, for eachcommunication parameter that is going to be adjusted, the determinedstart time, the target value, and the rate of change for thecommunication parameter to the satellite gateway of the wirelesscommunication channel to which the communication parameter applies. Inthe example of FIG. 1, the bandwidth controller 161 provides, forChannel 1, data specifying the determined start time, the target valuefor the center frequency (30.02 GHz), the target bandwidth (160 MHz),the rate of change for the center frequency (50 KHz per second), and therate of change for the bandwidth (100 KHz per second) to the satellitegateway 150. If the bandwidth controller 161 determined to adjust thecommunication parameters for another wireless communication channel, thebandwidth controller 161 can provide similar data to the satellitegateway that exchanges data using the other wireless communicationchannel.

In stage (F), the transmitter 152 of the satellite gateway 159 transmitschannel parameter data 170 to the satellite 140. The channel parameterdata 170 includes data specifying, for Channel 1, the determined starttime for the center frequency adjustment, the start time for thefrequency bandwidth adjustment (which may be the same as or differentfrom the start time of the center frequency), the target value for thecenter frequency (30.02 GHz), the target bandwidth (160 MHz), the rateof change for the center frequency (50 KHz per second), and the rate ofchange for the bandwidth (100 KHz per second). In stage (G), thesatellite 140 forwards the channel parameter data 170 to the terminal120.

In some implementations, the channel parameter data 170 is also providedto the receiver 153. In this way, the receiver 153 can adapt to theadjustments to the communication parameters as the adjustments occur.For example, the receiver 153 will know the center frequency and thefrequency bandwidth of Channel 1 on which the transmitter 124 will betransmitting data at any given time based on the start time(s) and therate(s) of change.

In stage (H), a channel adjuster 128 gradually adjusts the centerfrequency and the frequency bandwidth of the transmitter 124 based onthe channel data 170. The channel adjuster 128 can start adjusting thecenter frequency of the transmitter 124 when the current time equals thestart time for the center frequency adjustment. Similarly, the channeladjuster 128 can start adjusting the frequency bandwidth of thetransmitter 124 when the current time equals the start time for thefrequency bandwidth adjustment.

The channel adjuster 128 can gradually adjust the center frequency forthe transmitter 124 based on the rate of change for the center frequencyspecified by the channel parameter data 170. The channel adjuster 128can change the center frequency continuously or incrementally. Forexample, the channel adjuster 128 can adjust the center frequencycontinuously at a rate equal to the rate of change for the centerfrequency. In another example, the channel adjuster 128 can adjust thecenter frequency incrementally, e.g., every 100 milliseconds, eachsecond, or based on another appropriate time period). The channeladjuster 128 can send data to the transmitter 124 specifying theadjusted center frequency. In turn, the channel adjuster 128 can adjustthe center frequency of Channel 1 on which the transmitter 124 istransmitting data.

Similarly, the channel adjuster 128 can gradually adjust the frequencybandwidth for the transmitter 124 based on the rate of change for therate of change for the frequency bandwidth specified by the channelparameter data 170. The channel adjuster 128 can change the frequencybandwidth continuously or incrementally. For example, the channeladjuster 128 can adjust the frequency bandwidth continuously at a rateequal to the rate of change for the frequency bandwidth. In anotherexample, the channel adjuster 128 can adjust the frequency bandwidthincrementally, e.g., every 100 milliseconds, each second, or based onanother appropriate time period). The channel adjuster 128 can send datato the transmitter 124 specifying the adjusted frequency bandwidth. Inturn, the transmitter 124 can adjust the frequency bandwidth of Channel1 on which the transmitter 124 is transmitting data 124.

The channel adjuster 128 can adjust the center frequency based on therate of change for the center frequency until the center frequencyreaches the target value for the center frequency specified by thechannel parameter data 170. Similarly, the channel adjuster 128 canadjust the frequency bandwidth for the frequency bandwidth based on therate of change until the frequency bandwidth reaches the target valuefor the frequency bandwidth specified by the channel parameter data 170.

In some implementations, the transmitter 124 is configured to adjust thecenter frequency and/or frequency bandwidth based on the rate of changefor each communication parameter. In this example, the transceiver 122would not need a channel adjuster 128.

In the example of FIG. 1, the channel adjuster 128 gradually adjusts thecenter frequency of the transmitter 124 (the center frequency ofChannel 1) using the rate of change of 50 KHz per second until thecenter frequency reaches the target value of 30.02 GHz. Based on therate of change for the center frequency, this adjustment to the centerfrequency would take 400 seconds (20 MHZ/50 KHz per second). Similarly,the channel adjuster 128 gradually adjusts the frequency bandwidth ofthe transmitter 124 (the frequency bandwidth of Channel 1) using therate of change of 100 KHz per second until the frequency bandwidthreaches the target value of 160 MHz. Based on the rate of change for thefrequency bandwidth, this adjustment to the frequency bandwidth wouldtake 600 seconds (60 MHz/100 KHz per second).

The transmitter 124 and/or the receiver 153 can determine the timeperiod in which the adjustment will take place based on the starttime(s) and the rates of change. In this example, the transmitter 124and the receiver 153 can determine that the adjustment to the centerfrequency will occur during a 400 second time period that will begin atthe start time for the center frequency by dividing the adjustment tothe center frequency (20 MHz) by the rate of change for the centerfrequency (50 KHz per second). Similarly, the transmitter 124 and thereceiver 153 can determine that the adjustment to the frequencybandwidth will occur during a 500 second time period beginning at thestart time for the frequency bandwidth by dividing the adjustment to thefrequency bandwidth (60 MHz) by the rate of change for the frequencybandwidth (100 KHz per second).

At time T0, the center frequency for Channel 1 is 30 GHz, the valuebefore the adjustment. The lower frequency of Channel 1 is 29.050 GHzand the upper band of Channel 1 is 30.050 GHz at time T0. This providesthe initial frequency bandwidth of 100 MHz.

At time T1, which is one second after the channel adjuster 128 beganadjusting the center frequency and the frequency bandwidth of Channel 1,the center frequency of the transmitter 124 is 30.00005 GHz, which is 50KHz greater than the center frequency before the adjustment began.Similarly, a time T1, the frequency bandwidth of the transmitter 124 is100.010 GHz (30.05005 GHz-29.04995 GHz), which is 100 KHz greater thanthe frequency bandwidth before the adjustment began. At time T0+600seconds, both communication parameters have reached their respectivetarget values. The transmitter 124 can continue transmitting data usingthe target center frequency and the target frequency bandwidth, e.g.,until receiving new channel parameter data 170.

During the adjustment to the center frequency and the frequencybandwidth of Channel 1, the transmitter 124 and the receiver 153 canmaintain an active wireless communication link on Channel 1. Forexample, the transmitter 124 can continue transmitting data during theadjustment using the current center frequency and the current frequencybandwidth at the time of the transmission. For example, at time T1, thetransmitter 124 can transmit data using Channel 1 which, at that time,would have a center frequency of 30.00005 GHz and a frequency bandwidthof 100.010 GHz. As the adjustment to the center frequency and theadjustment to the frequency bandwidth are less than or equal to therespective maximum rates of the receiver 153, the receiver 153 canreceive the data transmitted at time T1 (and throughout entireadjustment) over Channel 1 without disruption to Channel 1.

The transmitter 124 can transmit more data at time T2 (not shown), whichmay be one second after T1. In this example, the transmitter 124 cantransmit data using Channel 1 which, at that time, would have a centerfrequency of 30.00010 GHz and a frequency bandwidth of 100.020 GHz. Asthe adjustment to the center frequency and the adjustment to thefrequency bandwidth are less than or equal to the respective maximumrates of the receiver 153, the receiver 153 can receive the datatransmitted at time T2 over Channel 1 without disruption to Channel 1.

In some implementations, the adjustments at the transmitter 124 are madebased on a different frequency band than the frequency band at which theterminal 120 transmits data to the satellite 140. For example, thetransmitter 124 may prepare data for transmission on the L-band (e.g.,1-2 GHz) and the terminal 120 can convert the output of the transmitter124 to the Ka-band or Ku-band. In this example, the channel adjuster 128(or transmitter 124) can convert the target values and rates of changefrom the Ka-band or Ku-band to the L-band before gradually making theadjustments. In another example, the rates of change may be stored interms of L-band rates of change and the target values may be specifiedin terms of L-band frequencies.

Although the example of FIG. 1 is described in terms of adjusting thecommunication parameters of a transmitter of a satellite terminal, thesame (or similar) techniques can be used to adjust the communicationparameters of a transmitter of a satellite gateway. In this example, therates of change of the communication parameters can be based on maximumrates of change for the satellite terminal's receiver. Further, the sametechniques of re-defining a wireless communication channel whilemaintaining an active connection can be used in wireless communicationssystems other than satellite systems. For example, for any appropriatewireless communication links, a system can determine a trackingcapability of a receiver and effectuate changes to channel parameters ina gradual manner, e.g., using incremental changes carried out in acoordinated, predetermined manner. The definition of a channel used by atransmitter and receiver can be gradually changed, rather thandisrupting communication by switching between use of two differentpre-defined channels.

FIG. 2 is a diagram 200 that illustrates an adjustment to thecommunication channel bandwidth of a wireless communication channel(Channel 1). Initially (e.g., before an adjustment to the communicationparameter(s) of Channel 1), Channel 1 has a center frequency (f_(c1)), alower frequency (f_(l1)), and an upper frequency (f_(u1)). Channel 1 hasa frequency bandwidth of f_(u1)-f_(l1).

In this example, the frequency bandwidth of Channel 1 is beingincreased, but the center frequency of Channel 1 is not being adjustedas there are no other wireless communication channels that would beaffected by the increase in frequency bandwidth of Channel 1. Thefrequency bandwidth of Channel 1 can be adjusted gradually based on arate of change for the frequency bandwidth of Channel 1 until a targetvalue for the frequency bandwidth of Channel 1 is reached.

After a first period of time during the adjustment, the frequencybandwidth of Channel 1 has increased from initial Channel 1 (201) tointermediate Channel 1 (202). The frequency bandwidth of intermediateChannel 1 (202) is the difference between the upper frequency (f_(u1′))of intermediate Channel 1 (202) and the lower frequency (f_(l1′)) ofintermediate Channel 1 (202). As the center frequency is not beingadjusted, the upper frequency and the lower frequency can be adjustedthe same amount.

After more time has elapsed, the frequency bandwidth of Channel 1 hasincreased from intermediate Channel 1 (202) to target Channel 1 (203).The frequency bandwidth of target Channel 1 (203) is the differencebetween the upper frequency (f_(u1″)) of intermediate Channel 1 (202)and the lower frequency (f_(l1″)) of target Channel 1 (203).

FIG. 3 is a diagram 300 that illustrates an adjustment to thecommunication channel bandwidth of a wireless communication channel(Channel 1). Initially (e.g., before an adjustment to the communicationparameter(s) of Channel 1), Channel 1 has a center frequency (f_(c1)), alower frequency (f_(u1)), and an upper frequency (f_(l1)). Channel 1 hasa frequency bandwidth of f_(u1)-f_(l1).

In this example, there is another wireless communication channel(Channel 2) adjacent to Channel 1. If the frequency bandwidth of Channel1 was increased without either increasing the center frequency (f_(c1))of Channel 1 or shifting Channel 2 to a lower frequency band (e.g., tothe left), the lower frequencies of Channel 1 would overlap with Channel2 and cause interference between Channel 1 and Channel 2. Thus, in thisexample, the frequency bandwidth of Channel 1 is gradually increased andthe center frequency of Channel 1 is gradually increased to prevent theoverlap and prevent the interference.

After a first period of time during the adjustment, the frequencybandwidth of Channel 1 has increased from initial Channel 1 (301) tointermediate Channel 1 (302). The center frequency of Channel 1 has alsoincreased from the initial center frequency (f_(c1)) to intermediatecenter frequency (fc_(1′)). The frequency bandwidth of intermediateChannel 1 (302) is the difference between the upper frequency (f_(u1′))of intermediate Channel 1 (302) and the lower frequency (f_(l1)) ofintermediate Channel 1 (302).

After more time has elapsed, the frequency bandwidth of Channel 1 hasincreased from intermediate Channel 1 (302) to target Channel 1 (303).The center frequency of Channel 1 has also increased from intermediatecenter frequency (f_(c1′)) to target center frequency (f_(c1″)). Thefrequency bandwidth of target Channel 1 (303) is the difference betweenthe upper frequency (f_(u1″)) of target Channel 1 (302) and the lowerfrequency (f_(l1)) of target Channel 1 (303).

In this example, the lower frequency (f_(l1)) of Channel 1 did not movefrom its initial value. In other examples, the lower frequency mayfluctuate, e.g., depending on the rate at which the center frequency andthe frequency bandwidth of Channel 1 are adjusted. For example, if thefrequency bandwidth was adjusted at a faster rate than the centerfrequency, the lower frequency may decrease below the initial value ofthe lower frequency until the center frequency is adjusted enough tobring the lower frequency back to its initial value. The start times ofthe adjustments to the center frequency and the frequency bandwidth ofChannel 1 can be determined to prevent the lower frequency fromdecreasing such that the frequency band of Channel 1 overlaps with thefrequency band of Channel 2.

FIG. 4 is a diagram 400 that illustrates adjustments to thecommunication channel bandwidth of multiple wireless communicationchannels (Channel 1 and Channel 3). Initially (e.g., before anadjustment to the communication parameter(s) of Channel 1), Channel 1has a center frequency (f_(c1)), a lower frequency (f_(l1)), and anupper frequency (f_(u1)). Channel 1 has a frequency bandwidth off_(u1)-f_(l1).

In this example, there is another wireless communication channel(Channel 2) adjacent to Channel 1 on the lower frequency side of Channel1 and another wireless communication channel (Channel 3) on the upperfrequency side of Channel 1. Thus, increasing the bandwidth of Channel 1to its target frequency bandwidth would cause Channel 1 to overlap withChannel 2 and/or Channel 3. To prevent such overlap and the interferencethat would result, Channel 3 is shifted to a higher frequency band andChannel 1 is adjusted such that its frequency band extends into theprevious frequency band of Channel 3.

After a first period of time during the adjustment, the initial centerfrequency of Channel 3 (f_(c3)) is increased to an intermediate centerfrequency (f_(c3′)). This shifts the frequency band of Channel 3 awayfrom the frequency band of Channel 1. The frequency bandwidth of Channel1 has also increased from initial Channel 1 (401) to intermediateChannel 1 (402). The center frequency of Channel 1 has also increasedfrom the initial center frequency (f_(c1)) to intermediate centerfrequency (fc_(1′)). The frequency bandwidth of intermediate Channel 1(402) is the difference between the upper frequency (f_(u1′)) ofintermediate Channel 1 (402) and the lower frequency (f_(l1)) ofintermediate Channel 1 (402).

After more time has elapsed, the frequency bandwidth of Channel 1 hasincreased from intermediate Channel 1 (402) to target Channel 1 (403).The center frequency of Channel 1 has also increased from intermediatecenter frequency (f_(c1′)) to target center frequency (f_(c1″)). Thefrequency bandwidth of target Channel 1 (303) is the difference betweenthe upper frequency (f_(u1″)) of target Channel 1 (403) and the lowerfrequency (f_(l1)) of target Channel 1 (403).

As shown in FIG. 4, the frequency band of target Channel 1 does notoverlap with the frequency band of shifted Channel 3. The communicationparameters of Channel 1 and Channel 3 can be adjusted gradually andcoordinated such that their frequency bands do not overlap at any pointduring the adjustments. For example, the start times for the adjustmentscan be determined based on the rates of change and the initial valuesfor the communication parameters of both channels such that the lowerfrequency of Channel 3 is shifted prior to the upper frequency ofChannel 1 would overlap with the lower frequency of Channel 3.

FIG. 5 is a diagram 500 that illustrates adjustments to thecommunication channel bandwidth of multiple wireless communicationchannels (Channels 1-5). In this example, the frequency bandwidth ofsome channels is increased and the frequency bandwidth of some channelsis reduced. The diagram 500 includes a before frequency spectrum 501that shows the frequency bands of Channels 1-5 before the adjustment andan after frequency spectrum 502 that shows the frequency bands ofChannels 1-5 after the adjustment.

The adjustments to the communication parameters of Channels 1-5 can becoordinated such that the frequency bands of the channels do not overlapat any time during the adjustment. For example, the frequency bandwidthof Channel 2 is being reduced and the frequency bandwidths of adjacentChannels 1 and 3 are being expanded into the frequency band previouslyoccupied by Channel 2. In this example, the start time for theadjustments to the communication parameters of Channels 1-3 can bedetermined such that the frequency band of Channel 2 is reduced beforethe adjustments to the frequency band of Channel 1 and the frequencyband of Channel 3 causes Channel 1 or Channel 3 to overlap with Channel2.

FIG. 6 is a diagram 600 that illustrates adjustments to multiplewireless communication channels. In this example, some wirelesscommunication channels are removed from the frequency spectrum and theremaining wireless communication channels are shifted to provideavailable bandwidth for wireless communication channels to be added tothe frequency spectrum.

The diagram 600 includes an initial frequency spectrum 601 that includesseven wireless communication channels (Channels 1-7). The diagram 600also includes an intermediate frequency spectrum 602. In theintermediate frequency spectrum 602, Channels 2, 4, and 6 have beenremoved. For example, the satellite terminals that were communicatingover Channels 2, 4, and 6 may have been deactivated. The removal ofChannels 2, 4, and 6 results in a fragmented spectrum in which there isextra bandwidth (e.g., more than a minimum amount used to separatechannels to prevent interference) between pairs of wirelesscommunication channels. If the fragmented frequency spectrum is notadjusted, any new wireless communication channel to be added to thefrequency spectrum would have to fit in one of the spaces left byChannels 2, 4, and 6 or wait until the remaining channels were adjustedto make room for the new channel.

As shown in the adjusted frequency spectrum 603, the remaining wirelesscommunication channels (Channels 1, 3, 5, and 7) can be adjusted, e.g.,to one side of the frequency spectrum, to make additional bandwidthspace for any new wireless communication channels. The remainingwireless communication channels can be shifted by gradually adjustingtheir respective center frequencies, as described above. The remainingwireless communication channels can be shifted in response to the otherwireless communication channels being removed from the frequencyspectrum, e.g., without waiting for a request to add a new wirelesscommunication channel to the frequency spectrum. In this way, a newwireless communication channel can be allocated more bandwidth than oneof the spaces left by Channel 2, 4, or 6, e.g., without waiting for theremaining channels to be shifted after receiving a request to add thenew wireless communication channel.

FIG. 7 is a flow diagram that illustrates an example process 700 foradjusting communication channel bandwidth. The process 700 may beperformed by a system that includes one or more computers. The one ormore computers can include one or more processors. The one or morecomputers can also include one or more data storage devices storinginstructions that, when executed, cause the one or more computers toperform the actions of the process 700. The steps of the process 600 maybe performed in the order shown in FIG. 7, or in another order.

In step (702), a determination is made to change a bandwidth of awireless communication channel, e.g., a satellite communication channelon which a satellite terminal is transmitting data to a satellitegateway. For example, a determination can be made to expand thefrequency bandwidth of the wireless communication channel in response toa request to expand the frequency bandwidth (e.g., received from atransmitter transmitting data over the wireless communication channel)or in response to historical bandwidth demand of the transmittertransmitting data over the wireless communication channel.

In another example, a determination may be made to adjust the frequencybandwidth of the wireless communication channel in response to anadjustment to a center frequency or frequency bandwidth of a differentwireless communication channel. In another example, a determination maybe made to adjust the frequency bandwidth of the wireless communicationchannel in response to an addition of a new communication channel to afrequency spectrum that includes the wireless communication channel orin response to removal of a wireless communication channel from thefrequency spectrum. In yet another example, a determination may be madeto adjust the frequency bandwidth of the wireless communication channelto make room in the frequency spectrum in case another wirelesscommunication channel is added later.

In step (704), a target value for each of one or more communicationparameters of the wireless communication channel is determined. The oneor more communication parameters can include at least one of (i) acenter frequency of the wireless communication channel or (ii) afrequency bandwidth of the wireless communication channel.

For example, a target frequency bandwidth for the wireless communicationchannel can be determined in response to the determination to adjust thefrequency bandwidth of the wireless communication channel. The targetfrequency bandwidth can be determined based on an amount of additional(or less) frequency bandwidth requested (or needed) for the wirelesscommunication channel and the amount of frequency bandwidth available.

A target value for the center frequency of the wireless communicationchannel can also be determined. For example, the frequency band of thewireless communication channel may be shifted based on the frequencyband(s) of adjacent wireless communication channel(s) as describedabove. To shift the frequency band of the wireless communicationchannel, a target center frequency that accomplishes the shift can bedetermined. As described above, the communication parameters of otherwireless communication channels can also be determined, e.g. to shiftthe wireless communication channels away from the wireless communicationchannel and make room for expanded bandwidth of the wirelesscommunication channel.

In step (706), a rate of change is identified for each of the one ormore communication parameters that are being adjusted is identified. Therate of change for each communication parameter can be a rate at whichthe communication parameter can be changed over time while continuing totransfer data on the wireless communication channel. For example, therate of change for a communication parameter can be less than or equalto a maximum rate of change for which the receiver that is receivingdata over the wireless communication channel is capable of tracking thechanges and maintaining an active wireless communication channel withthe transmitter that is transmitting data over the wirelesscommunication channel.

In step (708), data is provided to each transmitter for which acommunication parameter s being adjusted. The data provided to atransmitter can causes the transmitter to gradually adjust thecommunication parameter using the rate of change for the communicationparameter until the communication parameter reaches the target value forthe communication parameter. For example, the data provided to atransmitter can include, for each communication parameter of thetransmitter being adjusted, the determined target value for thecommunication parameter and the identified rate of change for thecommunication parameter. Each transmitter can gradually (e.g.,continuously or incrementally) adjust its communication parameter(s)using the rate of change for the communication parameter until thecommunication parameter reaches the target value for the communicationparameter.

The data provided to a transmitter can also include a start time foreach communication parameter of the transmitter being adjusted. Forexample, as described above, the starts times for the adjustments can bedetermined so that the frequency bands of the wireless communicationchannels do not overlap and cause interference during the adjustments tothe communication parameters. Each transmitter can use the start time(s)for its communication parameter(s) to determine when to start thegradual adjustment to the communication parameter(s).

Embodiments of the invention and all of the functional operationsdescribed in this specification may be implemented in digital electroniccircuitry, or in computer software, firmware, or hardware, including thestructures disclosed in this specification and their structuralequivalents, or in combinations of one or more of them. Embodiments ofthe invention may be implemented, in part, as one or more computerprogram products, i.e., one or more modules of computer programinstructions encoded on a computer-readable medium for execution by, orto control the operation of, data processing apparatus. The computerreadable medium may be a non-transitory computer readable storagemedium, a machine-readable storage device, a machine-readable storagesubstrate, a memory device, a composition of matter effecting amachine-readable propagated signal, or a combination of one or more ofthem. The term “data processing apparatus” encompasses all apparatuses,devices, and machines for processing data, including by way of example aprogrammable processor, a computer, or multiple processors or computers.The apparatus may include, in addition to hardware, code that creates anexecution environment for the computer program in question, e.g., codethat constitutes processor firmware, a protocol stack, a databasemanagement system, an operating system, or a combination of one or moreof them.

A computer program (also known as a program, software, softwareapplication, script, or code) may be written in any form of programminglanguage, including compiled or interpreted languages, and it may bedeployed in any form, including as a stand-alone program or as a module,component, subroutine, or other unit suitable for use in a computingenvironment. A computer program does not necessarily correspond to afile in a file system. A program may be stored in a portion of a filethat holds other programs or data (e.g., one or more scripts stored in amarkup language document), in a single file dedicated to the program inquestion, or in multiple coordinated files (e.g., files that store oneor more modules, sub programs, or portions of code). A computer programmay be deployed to be executed on one computer or on multiple computersthat are located at one site or distributed across multiple sites andinterconnected by a communication network.

The processes and logic flows described in this specification may beperformed by one or more programmable processors executing one or morecomputer programs to perform functions by operating on input data andgenerating output. The processes and logic flows may also be performedby, and apparatus may also be implemented as, special purpose logiccircuitry, e.g., an FPGA (field programmable gate array) or an ASIC(application specific integrated circuit).

While this specification contains many specifics, these should not beconstrued as limitations on the scope of the invention or of what may beclaimed, but rather as descriptions of features specific to particularembodiments of the invention. Certain features that are described inthis specification in the context of separate embodiments may also beimplemented in combination in a single embodiment. Conversely, variousfeatures that are described in the context of a single embodiment mayalso be implemented in multiple embodiments separately or in anysuitable subcombination. Moreover, although features may be describedabove as acting in certain combinations and even initially claimed assuch, one or more features from a claimed combination may in some casesbe excised from the combination, and the claimed combination may bedirected to a subcombination or variation of a subcombination.

Similarly, while operations are depicted in the drawings in a particularorder, this should not be understood as requiring that such operationsbe performed in the particular order shown or in sequential order, orthat all illustrated operations be performed, to achieve desirableresults. In certain circumstances, multitasking and parallel processingmay be advantageous. Moreover, the separation of various systemcomponents in the embodiments described above should not be understoodas requiring such separation in all embodiments, and it should beunderstood that the described program components and systems maygenerally be integrated together in a single software product orpackaged into multiple software products.

Thus, particular embodiments of the invention have been described. Otherembodiments are within the scope of the following claims. For example,the actions recited in the claims may be performed in a different orderand still achieve desirable results.

What is claimed is:
 1. A method performed by one or more computingdevices, the method comprising: obtaining data indicating a target valuefor a communication parameter of a wireless communication channel onwhich a transmitter is configured to transmit data; identifying amaximum rate of change for the communication parameter, the maximum rateof change being a rate at which the communication parameter can bechanged while data continues to be transferred on the wirelesscommunication channel; and providing, to the transmitter, data thatcauses the transmitter to gradually adjust the communication parameterat a rate of change that is less than or equal to the maximum rate ofchange for the communication parameter until the communication parameterreaches the target value for the communication parameter.
 2. The methodof claim 1, wherein the communication parameter comprises at least oneof a center frequency of the wireless communication channel or afrequency bandwidth of the wireless communication channel.
 3. The methodof claim 1, wherein: the transmitter communicates with a receiver overthe wireless communication channel; and whenever the communicationparameter is adjusted at a rate that exceeds the maximum rate of change,communication between the transmitter and the receiver over the wirelesscommunication channel is disrupted.
 4. The method of claim 1, wherein:adjusting the communication parameter by an amount that is equal to amagnitude of difference between the target value for the communicationparameter and a current value of the communication parameter disruptscommunication between the transmitter and a received over the wirelesscommunication channel; and the transmitter and received maintaincommunications over the wires communication channel when thecommunication parameter is adjusted at a rate of change that is lessthan or equal to the maximum rate of change for the communicationparameter.
 5. The method of claim 1, wherein: the transmittercommunicates with a receiver over the wireless communication channel;and the receiver tracks the communication parameter during the gradualadjustment to the communication parameter and continues to receive datafrom the transmitter during the gradual adjustment.
 6. The method ofclaim 5, wherein, in response to the transmitter adjusting thecommunication parameter at a second rate of change that exceeds themaximum rate of change for the communication parameter, the receiverfails to track the communication parameter and communication between thetransmitter and the receiver over the wireless communication channel isdisrupted.
 7. The method of claim 1, wherein: the transmitter comprisesa satellite transmitter that communicates with a satellite receiver; andthe satellite transmitter transmits data to the satellite receiver byway of a satellite and using a satellite communication link over thewireless communication channel.
 8. The method of claim 1, wherein: thetransmitter gradually adjusts the communication parameter over a timeperiod; the transmitter maintains an active communication link with areceived over the wireless communication channel during the time period;the receiver receives, from the transmitter, multiple data transmissionsover the wireless communication channel during the time period; and avalue of each of communication parameter is different for at least twoof the data transmissions.
 9. A system comprising: a data processingapparatus; and a computer storage medium storing instructions that, whenexecuted by the data processing apparatus, cause the data processingapparatus to perform operations comprising: obtaining data indicating atarget value for a communication parameter of a wireless communicationchannel on which a transmitter is configured to transmit data;identifying a maximum rate of change for the communication parameter,the maximum rate of change being a rate at which the communicationparameter can be changed while data continues to be transferred on thewireless communication channel; and providing, to the transmitter, datathat causes the transmitter to gradually adjust the communicationparameter at a rate of change that is less than or equal to the maximumrate of change for the communication parameter until the communicationparameter reaches the target value for the communication parameter. 10.The system of claim 9, wherein the communication parameter comprises atleast one of a center frequency of the wireless communication channel ora frequency bandwidth of the wireless communication channel.
 11. Thesystem of claim 9, wherein: the transmitter communicates with a receiverover the wireless communication channel; and whenever the communicationparameter is adjusted at a rate that exceeds the maximum rate of change,communication between the transmitter and the receiver over the wirelesscommunication channel is disrupted.
 12. The system of claim 9, wherein:adjusting the communication parameter by an amount that is equal to amagnitude of difference between the target value for the communicationparameter and a current value of the communication parameter disruptscommunication between the transmitter and a received over the wirelesscommunication channel; and the transmitter and received maintaincommunications over the wires communication channel when thecommunication parameter is adjusted at a rate of change that is lessthan or equal to the maximum rate of change for the communicationparameter.
 13. The system of claim 9, wherein: the transmittercommunicates with a receiver over the wireless communication channel;and the receiver tracks the communication parameter during the gradualadjustment to the communication parameter and continues to receive datafrom the transmitter during the gradual adjustment.
 14. The system ofclaim 13, wherein, in response to the transmitter adjusting thecommunication parameter at a second rate of change that exceeds themaximum rate of change for the communication parameter, the receiverfails to track the communication parameter and communication between thetransmitter and the receiver over the wireless communication channel isdisrupted.
 15. The system of claim 9, wherein: the transmitter comprisesa satellite transmitter that communicates with a satellite receiver; andthe satellite transmitter transmits data to the satellite receiver byway of a satellite and using a satellite communication link over thewireless communication channel.
 16. The system of claim 9, wherein: thetransmitter gradually adjusts the communication parameter over a timeperiod; the transmitter maintains an active communication link with areceived over the wireless communication channel during the time period;the receiver receives, from the transmitter, multiple data transmissionsover the wireless communication channel during the time period; and avalue of each of communication parameter is different for at least twoof the data transmissions.
 17. A non-transitory computer readable mediumcomprising instructions that, when executed by a data processingapparatus, cause the data processing apparatus to perform operationscomprising: obtaining data indicating a target value for a communicationparameter of a wireless communication channel on which a transmitter isconfigured to transmit data; identifying a maximum rate of change forthe communication parameter, the maximum rate of change being a rate atwhich the communication parameter can be changed while data continues tobe transferred on the wireless communication channel; and providing, tothe transmitter, data that causes the transmitter to gradually adjustthe communication parameter at a rate of change that is less than orequal to the maximum rate of change for the communication parameteruntil the communication parameter reaches the target value for thecommunication parameter.
 18. The non-transitory computer readable mediumof claim 17, wherein the communication parameter comprises at least oneof a center frequency of the wireless communication channel or afrequency bandwidth of the wireless communication channel.
 19. Thenon-transitory computer readable medium of claim 17, wherein: thetransmitter communicates with a receiver over the wireless communicationchannel; and whenever the communication parameter is adjusted at a ratethat exceeds the maximum rate of change, communication between thetransmitter and the receiver over the wireless communication channel isdisrupted.
 20. The non-transitory computer readable medium of claim 17,wherein: adjusting the communication parameter by an amount that isequal to a magnitude of difference between the target value for thecommunication parameter and a current value of the communicationparameter disrupts communication between the transmitter and a receivedover the wireless communication channel; and the transmitter andreceived maintain communications over the wires communication channelwhen the communication parameter is adjusted at a rate of change that isless than or equal to the maximum rate of change for the communicationparameter.